Modern computers have hard drives that are made in the form of a headstack and a stack of hard disks. A headstack is an assembly that includes one or more read and write heads, which are stacked in such a manner as to work in conjunction with the pack of hard disks, which are used for data storage. These devices are well known and are used in many data storage applications. The headstacks are manufactured by many companies such as SAE Magnetics, Western Digital (Read-Rite), Hitachi Global Storage Technologies (IBM), Seagate, and others. The headstack is generally mounted on a shaft by means of bearings, which allows the headstack to rotate freely on the shaft. During data storage operations (reading and writing), the magnetic heads are turned on the shaft to position them with respect to the hard disks.
A magnetic head and disk tester is an instrument that is used for testing the characteristics of magnetic heads and disks, such as a signal-to-noise ratio, track profile, etc. The tester simulates those motions of the head with respect to the disk and the same rotational speeds of the disks that occur in an actual hard disk drive during operation. Each tester consists of two components, i.e., a mechanical component, commonly referred to as a spinstand, that performs movements of the head with respect to the disk, and an electronic component that is responsible for measurement, calculation, and analysis of the measured signal. The spinstand is also a mechanical component of a servo-writer, an instrument that is used for writing servo information on a magnetic disk, as well as a component of a flying height tester; an instrument used for measuring the flying height of a head over the disk.
An example of a prior art spinstand for a head and disk tester is illustrated in FIGS. 1 and 2. The spinstand 100 includes a stationary base plate 110 that supports walls 112a, 112b, 112c. The walls 112a, 112b, 112c in turn support a spindle 113 for carrying a disk pack DP disposed in a cylindrical disk pack region including one or more magnetic disks 114, having diameter D, and being coaxial about a disk pack axis DPA. The spindle 113 and the disks 114 are rotated by a spindle motor 115 about a spin axis SA.
The base plate 110 further supports first and second slide motors (not shown). The first slide motor moves a slide 116 along rails 117a, 117b in the Y direction (see FIG. 2). Two additional rails, 118a, 118b, are mounted on top of slide 116. The second slide motor controls movement of a second slide 119 along rails 118a, 118b in the X direction. The first and second motors cooperate to position a headstack 120 mounted on a headstack locator 121 of the slide 119 to a specified location with respect to the center of spindle 113. The headstack 120 carries and positions magnetic head(s) 122 relative to disk(s) 114.
Other examples of prior art spinstands for a head and disk tester include the Guzik V2002 XY-positioning spinstand and the Guzik S-1701 Series Micro Positioning Spinstand, all of which are available from the assignee of the present disclosure, Guzik Technical Enterprises, 2443 Wyandotte Street, Mountain View, Calif. 94043, USA (www.guzik.com).
As the density of magnetic recording increases, additional information tracks are compressed into a given disk area. The decrease in track size heightens the demand for improved accuracy in head positioning. Likewise, the rotational speeds of the magnetic disks increase in order to achieve shorter access times. In addition, more disks are added to the disk stack to provide additional storage.
As the disk(s) rotate, vibrations in both the disks and the magnetic heads may be induced. These vibrations increase track misregistration. In some cases, track misregistration between the disks and the magnetic heads reaches unacceptable levels at which spinstand operation becomes unreliable.
What is still desired is a new and improved apparatus and method for locating and fixing a headstack on a spinstand. Among other aspects and advantages, the new and improved apparatus and method will quickly and accurately locate and secure a headstack to a spinstand for testing, while retaining the reliability and stability of all previous methods.
While the above background discusses coupling elements that are commonly used in headstacks and spinstands, there is a need for apparatus and methods for generally locating and reversibly coupling various elements to each other.